1. Field of the Invention
The present invention generally relates to an apparatus and method for implementing flow management and packet classification in a Cable Modem Termination System (CMTS).
2. Description of the Related Art
The development of computer related technologies in recent years has fueled growth of the Internet. Internet users are now regularly using the Internet to browse news information, shop, make travel arrangements, communicate with other users via e-mail, and interactively communicate with other users via voice/video over Internet protocol applications, to name a few things. In the workplace, Internet connections are generally provided through a corporate data communications network, such as a LAN, that interfaces with a high speed Internet connection, such as a dedicated digital or T1 line. However, the vast majority of personal/home users of the Internet utilize modem connections to access the Internet through a public switched telephone network (PSTN) through their home telephone line. In this configuration, the PSTN provides a dedicated connection from the home personal computer (PC) to a server generally located on the premises of an Internet service provider. The PSTN connection, which is generally provided through a normal telephone line, is capable of transmitting data at rates ranging from 14,400 bps up to 56,000 bps, the maximum data throughput rate under current regulations for PSTN-type connections. Although the modem-type connection through a PSTN is generally available in most all areas, these types of connections suffer from bandwidth limitations, as current computing applications often require data throughput rates greater than 56,000 bps for effective operation.
In response to the bandwidth limitations of general modem connections, the industry is now turning to alternative methods of connecting to the Internet. A popular alternative to the general modem-type connection is the recently developed Cable Modem (CM) technology. This technology utilizes the cable television infrastructure to transmit and receive Internet related data from a home-computing source. In a typical configuration, a personal computer is equipped with a cable modem that interfaces with an existing coaxial or hybrid fiber/coaxial cable (HFC) used to provide cable television service to the home. This coaxial cable is then used to transmit both Internet and television signals to the home. Additionally, since the coaxial cable system is capable of data transfer rates of 30+ Mbps, a substantially greater bandwidth is available through these types of systems. Furthermore, since CM-type systems share a single coaxial cable for many users, the resources required to support the growing number of Internet users is decreased.
Notwithstanding the increase in bandwidth of cable modems, network congestion in a cable modem-type system is still a factor. In particular, when an Internet user is using latency sensitive applications, such as voice/video over IP applications, it is critical that data frames related to these types of software applications be routed through the data network ahead of regular data frames, as voice/video over IP (VoIP) data frames are more sensitive to data transmission delays that result from network congestion. Therefore, a need for a cable modem capable of traffic policing, rate shipping, and scheduling, all of which are commonly referred to as flow management, along with data classification capabilities, plainly exists.